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12-8
Chapter 12
Theory of Operation
Power Supply Theory
Shutdown Circuit
The shutdown circuit is triggered by overcurrent, overvoltage, undervoltage, or
overtemperature. It protects the instrument by causing the regulated voltage supplies to
be shut down. It also sends status messages to the A9 CPU to trigger warning messages on
the analyzer display. The voltages that are not shut down are the +5 VD and +5 VCPU
digital supplies from the preregulator, the fan supplies, the probe power supplies, and the
display supplies. The shutdown circuit can be disabled momentarily for troubleshooting
purposes by using a jumper to connect the SDIS line (A8TP4) to ground.
Variable Fan Circuit and Air Flow Detector
The fan power is derived directly from the +18 V and
−
18 V supplies from the A15
preregulator. The fan is not fused, so that it will continue to provide airflow and cooling
when the instrument is otherwise disabled. If overheating occurs, the main instrument
supplies are shut down and the fan runs at full speed. An overtemperature status message
is sent to the A9 CPU to initiate a warning message on the analyzer display. The fan also
runs at full speed if the air flow detector senses a low output of air from the fan. (Full
speed is normal at initial power on.)
Display Power
The A8 assembly su5 VCPU to the A19 GSP through the motherboard. The GSP
converts a portion of the +5 VCPU to 3.3 V to drive the display and LVDS (low voltage
differential signaling) logic. The A19 GSP also controls and supplies power to the A27
backlight inverter. The voltages generated by the inverter are then routed to the display.
Display power is not connected to the protective shutdown circuitry so that the A18 display
assemblies can operate during troubleshooting when other supplies do not work.
NOTE
If blanking pulses from the A19 GSP are not present, then +3.3 V will
not be sent to the display.
Probe Power
The +18 V and
−
18 V supplies are post regulated to +15 V and
−
12.6 V to provide a power
source at the front panel for an external RF probe or millimeter modules.
Содержание 8753ES
Страница 14: ...Contents xiv Contents ...
Страница 15: ...1 1 1 Service Equipment and Analyzer Options ...
Страница 26: ...1 12 Chapter1 Service Equipment and Analyzer Options Service and Support Options ...
Страница 27: ...2 1 2 System Verification and Performance Tests ...
Страница 202: ...2 176 Chapter2 System Verification and Performance Tests Agilent 8753ET Performance Test Records ...
Страница 203: ...3 1 3 Adjustments and Correction Constants ...
Страница 262: ...3 60 Chapter3 Adjustments and Correction Constants Sequences for Mechanical Adjustments ...
Страница 263: ...4 1 4 Start Troubleshooting Here ...
Страница 297: ...5 1 5 Power Supply Troubleshooting ...
Страница 305: ...Chapter 5 5 9 Power Supply Troubleshooting If the Red LED of the A15 Is ON Figure 5 5 Power Supply Cable Locations ...
Страница 317: ......
Страница 318: ...6 1 6 Digital Control Troubleshooting ...
Страница 337: ...6 20 Chapter6 Digital Control Troubleshooting GPIB Failures ...
Страница 338: ...7 1 7 Source Troubleshooting ...
Страница 369: ...7 32 Chapter7 Source Troubleshooting Source Group Troubleshooting Appendix ...
Страница 370: ...8 1 8 Receiver Troubleshooting ...
Страница 381: ...8 12 Chapter8 Receiver Troubleshooting Troubleshooting When One or More Inputs Look Good ...
Страница 382: ...9 1 9 Accessories Troubleshooting ...
Страница 389: ...9 8 Chapter9 Accessories Troubleshooting Inspect the Error Terms ...
Страница 390: ...10 1 10 Service Key Menus and Error Messages ...
Страница 439: ...10 50 Chapter10 Service Key Menus and Error Messages Error Messages ...
Страница 440: ...11 1 11 Error Terms ...
Страница 451: ...11 12 Chapter11 Error Terms Error Correction ...
Страница 452: ...12 1 12 Theory of Operation ...
Страница 461: ...12 10 Chapter12 Theory of Operation Digital Control Theory Figure 12 3 Digital Control Group Simplified Block Diagram ...
Страница 482: ...13 1 13 Replaceable Parts ...
Страница 487: ...13 6 Chapter13 Replaceable Parts Ordering Information Figure 13 1 Module Exchange Procedure ...
Страница 490: ...Chapter 13 13 9 Replaceable Parts Replaceable Part Listings This page intentionally left blank ...
Страница 492: ...Chapter 13 13 11 Replaceable Parts Replaceable Part Listings Figure 13 2 8753ET Major Assemblies Top ...
Страница 494: ...Chapter 13 13 13 Replaceable Parts Replaceable Part Listings Figure 13 3 8753ES Major Assemblies Top ...
Страница 498: ...Chapter 13 13 17 Replaceable Parts Replaceable Part Listings This page intentionally left blank ...
Страница 500: ...Chapter 13 13 19 Replaceable Parts Replaceable Part Listings Figure 13 7 8753ET Cables Top ...
Страница 502: ...Chapter 13 13 21 Replaceable Parts Replaceable Part Listings Figure 13 8 8753ES Cables Top ...
Страница 504: ...Chapter 13 13 23 Replaceable Parts Replaceable Part Listings This page intentionally left blank ...
Страница 506: ...Chapter 13 13 25 Replaceable Parts Replaceable Part Listings Figure 13 10 8753ET Cables Bottom ...
Страница 508: ...Chapter 13 13 27 Replaceable Parts Replaceable Part Listings Figure 13 11 8753ES Cables Bottom ...
Страница 510: ...Chapter 13 13 29 Replaceable Parts Replaceable Part Listings Figure 13 12 8753ET Cables Front 8753ET Option 004 ...
Страница 512: ...Chapter 13 13 31 Replaceable Parts Replaceable Part Listings Figure 13 13 8753ES Cables Front ...
Страница 514: ...Chapter 13 13 33 Replaceable Parts Replaceable Part Listings Figure 13 14 8753ET ES Cables Rear ...
Страница 518: ...Chapter 13 13 37 Replaceable Parts Replaceable Part Listings Figure 13 17 8753ET ES Front Panel Assembly Outside ...
Страница 520: ...Chapter 13 13 39 Replaceable Parts Replaceable Part Listings Figure 13 18 8753ET ES Front Panel Assembly Inside ...
Страница 522: ...Chapter 13 13 41 Replaceable Parts Replaceable Part Listings Figure 13 19 8753ET Rear Panel Assembly ...
Страница 524: ...Chapter 13 13 43 Replaceable Parts Replaceable Part Listings Figure 13 20 8753ES Rear Panel Assembly ...
Страница 526: ...Chapter 13 13 45 Replaceable Parts Replaceable Part Listings Figure 13 21 8753ET ES Rear Panel Assembly Option 1D5 ...
Страница 528: ...Chapter 13 13 47 Replaceable Parts Replaceable Part Listings Figure 13 22 8753ET ES Hardware Top ...
Страница 538: ...Chapter 13 13 57 Replaceable Parts Replaceable Part Listings Figure 13 31 8753ET ES Chassis Parts Outside ...
Страница 544: ...14 1 14 Assembly Replacement and Post Repair Procedures ...
Страница 550: ...Chapter 14 14 7 Assembly Replacement and Post Repair Procedures Covers Figure 14 2 Covers ...
Страница 552: ...Chapter 14 14 9 Assembly Replacement and Post Repair Procedures Front Panel Assembly Figure 14 3 Front Panel Assembly ...
Страница 558: ...Chapter 14 14 15 Assembly Replacement and Post Repair Procedures Rear Panel Assembly Figure 14 6 Rear Panel Assembly ...
Страница 562: ...Chapter 14 14 19 Assembly Replacement and Post Repair Procedures A3 Source Assembly Figure 14 8 A3 Source Assembly ...
Страница 568: ...Chapter 14 14 25 Assembly Replacement and Post Repair Procedures A9 CPU Board Figure 14 11 A9 CPU Board ...
Страница 570: ...Chapter 14 14 27 Assembly Replacement and Post Repair Procedures A9BT1 Battery Figure 14 12 A9BT1 Battery ...
Страница 572: ...Chapter 14 14 29 Assembly Replacement and Post Repair Procedures A15 Preregulator Figure 14 13 A15 Preregulator ...
Страница 588: ...Chapter 14 14 45 Assembly Replacement and Post Repair Procedures A23 LED Board 8753ES Only Figure 14 20 A23 LED Board ...
Страница 597: ...14 54 Chapter14 Assembly Replacement and Post Repair Procedures Post Repair Procedures ...
Страница 598: ...15 1 15 Safety and Regulatory Information ...